Selective sorption process



Patented Nov. 1 5, 1 949 SELECTIVE SORPTION PROCESS Donald A. Hermanson, Plainfield, N. J., assignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application October 4, 1947, Serial No. 778,043

14 Claims.

This invention relates to a selective sorption process and, more particularly, is concerned with a method for separating hydrocarbon mixtures by contacting the same with a solid porous sorbent particle-form material, the pores of which are substantially filled with a gaseous material soluble in the sorbed component of said hydrocarbon mixture, thereby efiecting a substantially rapid separation between the comparatively lower molecular volume and higher molecular volume components of said mixture by sorption of the former into the pores of the contact material, While the latter remain unsorbed.

The process of the present invention is a modification of the procedure described in co-pending application Serial Number 655,581, filed March 19, 1946, now abandoned. It was there disclosed that non-gaseous mixtures, at least one component of which is a liquid, may be separated by contacting the same with particles of a porous sorbent medium under conditions of contact such that the low viscosity, lighter components of the mixture were sorbed, leaving the high viscosity, heavier components unsorbed, thus effecting a separation of the mixture into two fractions.

In accordance with the present invention, it has now been discovered that the nature of the material present in the pores of the solid particleform sorbent material employed, when contact is made with the mixture to be treated, has considerable effect on both the rate and selectivity of the sorption process. More specifically, it has been found that if the air normally present in the pores of the sorbent medium is replaced by a gaseous material soluble in the sorbed component of the mixture being treated, the rate of sorption can be substantially increased without interfering with the selectivity of the operation.

The process of this invention may be employed in separating non-gaseous complex mixtures containing at least one liquid component whenever two or more of the components comprising said mixture differ in molecular volume. The process of this invention may thus be used in separating the components of animal, vegetable, marine and mineral oils, waxes, resins, and similar mixtures. The selective sorption method described herein is particularly adaptable for the separation of hydrocarbon mixtures, such as those found in petroleum, into fractions having a low viscosityhigh viscosity index and light color in comparison to the oil charge being treated and other fractions having a higher viscosity and a darker color than the original oil.

It has been found that porous contact materials, having a structure corresponding to that of an inorganic oxide gel having a substantially uniform porosity of low macropore volume with an average pore diameter not exceeding about 125 Angstrom units and a particle size preferably not smaller than about 30 mesh for most operations, have the ability to sorb the light components of a liquid hydrocarbon fraction while leaving substantially unsorbed, the darker, more viscous components. In this respect, the process of the present invention is to be distinguished from the decolorizing of petroleum oil by contacting the same with clay, bauxite, and similar materials, whereby the dark, heavier components of the oil are removed, leaving behind the lighter components. It will thus be seen that the action of these latter adsorbents is the reverse of that encountered in the selective sorption process described herein.

The macropore volume of the contact material employed in the present invention should be relatively low so that the pore volume is substantially that of micropores. In general, the volume of macropores, that is, those pores having radii larger than Angstrom units, should constitute less than about 30 per cent of the total pore volume, and preferably 10 per cent or less. The measurement of pore size and pore size distribution in various porous materials is discussed in detail by L. C. Drake and H. L. Ritter in Industrial and Engineering Chemistry, Analytical Edition, volume 17, pages 782-791 (1945). The methods described there were essentially those employed in determining the bulk densities, average pore diameters, and other pore measurements of the absorbents employed in the present invention.

The size of the sorbent particles employed in the process of this invention is to some extent dependent upon the variables involved in any particular application of the process. These important variables are: time of contact between the liquid mixture under treatment and the sorbent in the sorption zone, temperature in the sorption zone, viscosity of the liquid charge, and, to a lesser extent, the ratio of liquid mixture to sorbent charged to the sorption zone. Increasing time of contact results in a decrease in the efiiciency of the desired separation. Decreasing viscosity of the liquid charge has the same effect. On the other hand, increasing temperature and decreasing viscosity both result in more rapid sorption of the lighter, less viscous components of the mixture. If the ratio of sorbent to liquid charge is excessive, some loss in separation efficiency results. By proper control of these variables, some latitude in the average diameter of the sorbent employed maybe provided. However, when the diameter of the particles becomes too small, the sorbent preferentially sorbs the heavier, more viscous components from the charge mixture in the same manner as well known decolorizing clays. This is shown in Table I below, in which is tabulated the results obtained upon sepe aration of a mid-continent residuum using a silica-alumina gel type sorbent having a bulk density in the 4-8 mesh size range of about 0.7.

In general, it may be said that the particle size of the sorbent material, particularly in the case of inorganic oxide gel type sorbents, should be less than about 60 mesh Tyler and preferably within the range of about 0.022 to 1.0 inch average diameter. The best results may be obtained by limiting the sorbents within the range of 0.03 to 0.20 inch average diameter and of reasonably uniform size. It is pointed out, however, that by proper control of the variables discussed hereinabove and also of the average pore diameter of the sorbent, operation according to the method of this invention may be obtained on sorbent particles outside the size ranges given, although the results will be less satisfactory. It is contemplated that, in its broader aspects, this invention covers these latter Table I Experiment Number 1 4 5 7 2 3 Charge Viscosity, S. U. V 116. 9 116.9 81. 8 81.8 81.8 81.8 340 harg Ramsbottom Carbon. 2,3 2.3 2.3 2. 3 5,1 Mesh Size of Sorbent (Tyler). 48 -60 30-60 -80 30-60 4-8 4-8 Sorption Zone Contact Time 24 hrs. 24 hrs 2 min. 2 min. 2 hrs. 72 hrs. 4 hrs. Sorption Zone Temperature, F 150 150 150 150 150 75 275 Weight Ratio of Sorbent to Liquid Charge 1 1 1 1 l 1 2- 2 Properties of Oily Constituent Retained by Sorbent:

S. U. V. 210 F. sec 69.7 129.2 75. 2 81. 7 115.4 49. 7 151 Ramsbottom Carbon, percent 1.8 2. 3 3. 1 2.4 Properties of Materials Washed from Sorbent Surface:

S. U. V. 210 F. sec 164 100.1 85.9 80.5 76.0 139.2 650 Ramsbottom Carbon, percent 2.4 2. 2 2.0 3. 5 6. 7

It will be apparent from the above Table I that when the gel type particles were greater than 30 mesh size, even at relatively high temperatures and long contact periods, the oily constituents of low viscosity and carbon residue were sorbed in the pores of the sorbent, while the more viscous,

heavier constituents could be washed away with a suitable washing solvent, in this case benzol. On the other hand, in the case of sorbent particles ranging from 30 to 60 mesh size, when the contact period was 24 hours (experiment 4) or even 2' hours (experiment 7), the sorbent acted similar to a normal filtering clay and preferentially sorbed the heavier, more viscous constituents; but when the contact time was reduced to 2 minutes (experiment 5), the 30-60 mesh sorbent exhibited a preference for the lighter, less viscous constituents over the heavier, more viscous constituents. When the particle size was reduced below 60 mesh, the sorbent preferentially sorbed the heavier, viscous constituents, even at very low contact periods (experiment 6).

The effect of contact time and temperature is shown in Table 11 below, in which are tabulated the results obtained upon separation of an East Texas residuum having an original Saybolt Universal viscosity of 512 seconds at 210 F. and a Ramsbottom carbon residue of 11.1. In this experiment, a silica-alumina gel type sorbent of 4-8 mesh size and 0.48 bulk density were employed.

operations as well as the specified preferred limits.

The porosity of the gel particles employed in the process of this invention is of fundamental importance. The degree of porosity is generally reflected in the bulk density of the gel composite used; the lower the bulk density, the greater being the degree of porosity. For the purposes of the present process, porous sorbent particles having bulk densities of between about 0.4 and 1.1 grams per cubic centimeter are preferred. The bulk densities indicated correspond to an average pore diameter of between about 20' and about 125 Angstrom units. Preferably, the sorbent used will have a bulk density between about 0.6 and about 0.8 gram per cubic centimeter. Gel particles having a bulk density greater than about 0.8 have been found to have excellent selectivity but poor sorbing capacity, while particles with a bulk density less than about 0.6 have relatively poor selectivity. However, since the selectivity of the separation process improves with a decrease in temperature, particles with a bull; density of less than 0.6 would be satisfactory for treating stocks which can be processed at low temperatures.

The degree of porosity of a synthetic inorganic oxide gel will, in general, depend on the conditions under which it is prepared and allowed to operations within the set to gelation. A particularlyconvenient method of preparing gel particles used in the process of this invention is described in U. S. Patent 2384,- 946, issued September 18, 1945, to Milton M. Marisic. It is there disclosed that spheroidal particles of inorganic oxide gel may be prepared by mixing an acidic stream with a stream of sodium silicate and allowing the resulting sol to be ejected from a nozzle into an oil column, where the gel sets in the form of bead-like spheroids. The resulting gel spheres, after washing, drying and tempering, were of a size varying between about 4 and about 20 mesh. The gel beads so produced had a bulk density of between about 0.4 and about 1.1 and an average pore diameter of between about 20 and about 125 Angstrom units. They proved to be excellent selective absorbents for use in the process of this invention.

Likewise, irregularly shaped porous absorbent fragments or particles having the structure of inorganic oxide gels may be used. However, in general, spheroidal particles are to be preferred, since attrition losses are then at a minimum and contamination with gel fines of the mixture undergoing treatment is substantially eliminated.

In general, siliceous gel particles will be used in the process of this invention, such as silica gel, silica-alumina gel, silica-zirconia gel, silicathoria gel, and the like. Porous sorptive silica glasses having a structure approaching that of a siliceous gel likewise are contemplated for use in the process described herein, it being necessary, however, that the porous glasses employed have an average pore diameter less than about 125 Angstrom units, and a macropore volume of less than .about 30 per cent of the total pore volume. The size of the porous glass particles must also be carefully controlled so as to obtain preferential sorption of the lighter, less viscous constituents of the mixture. Usually, particles of less than 60 mesh size are undesirable. It is also contemplated that, within the scope of this invention, other porous materials not of siliceous gel composition which have structures approaching that of an inorganic oxide gel and are within the above specified pore size and particle size may be employed in the selective sorption process of this invention.

Typical of the porous glasses used are those described in U. S. Patent 2,106,744, issued February l, 1938, to Hood et al. There it is disclosed that a silica-alkali-boric oxide glass of suitable composition is prepared by a fusion process. Heat treatment of this glass results in separation of the glass into two phases; one phase is rich in alkali-boric oxide and is soluble in acids, while the other phase, which is insoluble in acid, consists of silica with a small amount of boric oxide. Extraction of this heat treated glass with acid results in a porous silica glass which can be employed as a porous absorbent separating medium in accordance with the present invention.

The displacement of air, normally present in the pores of the above defined contact material, with a suitable gaseous material may be effected in any desired manner. Thus, the air may be displaced from the pores of the inorganic gel type contact material by diffusion with a stream of gas or vapor. An alternate procedure involves subjecting the particles of porous contact material to a vacuum to remove substantially all the air present in the pores and then bringing the evacuated particles into contact with the gaseous material to be employed. Another way of replacing the air with suitable vapor is to soak containing sorbed material.

the sorbent particles in a solvent until all the air has been displaced. This point will be reached when air bubbles are no longer evolved from the absorbent. The excess solvent is then removed and the remaining solvent-saturated particles heated to a temperature at which vaporization of the solvent begins to occur. The temperature is maintained at this level until substantially all of the solvent present in the pores of the contact material is vaporized. The particles filled with solvent vapor are then brought into contact with the mixture to be treated. An effective method for displacing air from the pores of the contact material comprises soaking the particles in a solvent until all the air has been replaced, removing the excess unsorbed solvent and subjecting the saturated particles to a high vacuum to vaporize the remaining solvent. The mixture to be separated is then added while the particles are still under vacuum, and then at completion of the addition of the mixture, the vacuum is broken and sorption takes place at atmospheric pressure.

The process of this invention is accordingly carried out by bringing a non-gaseous mixture containing components of difiering molecular volume and at least one of which is a liquid in contact with a particle-form, porous medium having a structure of an inorganic oxide gel, the pores of which are substantially filled with a gaseous material soluble in the component of the mixture to be sorbed. The components of the mixture not sorbed may thereafter be separated from the porous particles Gaseous materials suitable for replacing air in the pores of the sorbent medium include both normally gaseous materials and vapors of materials which are normally found in the liquid or solid state. Generally, the pores of the sorbent used will be substantially filled with gaseous material. However, the process of this invention also contemplates the use of a sorbent medium having a partial displacement of the air contained in its pores with a suitable gaseous material. The proportion of air displaced by said gaseous material will generally be such as to effect a noticeable increase in the rate of sorption. The contacting is carried out in any suitable vessel where direct contact between particles of sorbent and the mixture to be separated is effected. The porous particles sorb the lower molecular volume components present in the mixture as liquids, while the higher molecular volume components remain unsorbed.

The temperature at which the contacting step is conducted may vary over wide limits, depending to a large extent on the nature of the mixture undergoing treatment. The minimum usable temperature is, in general, the lowest temperature at which the liquid component of lowest freezing point will flow. The maximum temperature at which the selective sorption process can be carried out is usually governed by the viscosity of the mixture being treated. The sorption becomes less selective as the viscosity of the mixture decreases. Thus, where the mixture being separated is a mineral oil fraction, the lowest temperature usable is that at which the oil will flow and the maximum temperature will be dependent on the viscosity of the fraction being separated. For a distillate stock, the maximum temperature may be below room temperature, while a heavy residual stock can be selectively separated at tempera- I tures as high as about 350 F.

The time required for the selective sorption process to take place depends upon the degree of separation" desiredand also upon: the; conditions on the: contact", such as? the nature of the: gaseous materiaL occupying the: pores of. the absorbent, the viscosity of the mixture being: treated, tempera-' ture;. and the like. In general, saturation of the sorbent' particles. with the. liquid lniXture is not required and excessive contact time: is to be avoided. since it has generally been found to reduce: the selectivity of the operation.

. When-the processrof this invention is employed in separating a. mineral oil' fraction, the. weightratio of sorbent. tooil will generally be between. about 0.5 and 3. Witha weight ratio lower than that indicated, the sorbed fraction will generally be very small in proportion to the unsorbed fraction. The. higher ratios. will usually be employed withtheasorbents of higher: density whose'sorbing capacity is smaller. An approximately equalweight mixture of oil and sorbent has been found to. be particularly effective under'the usual operation conditions.

Thesubsequent removal of unsorbed material from the porous sorbent particles may be accomplishedby one of a. number of methods, dependinglom the type of material contacted. If both. the high and. low: molecular volume components of the. mixture undergoing separation are liquids, the unsorbed material is. allowed to drain or may he centrifuged: A- certain'. amount of unsorbed'. material adheres. to the surface. of the. contact. particles and this. is removed by washing with a suitable: solvent- If the: unsorbed' material is a. solid; separation may be: accomplished by screening, solvent washing, use. of. air currents to lift theilighterimaterial, or'other suitable methods.-v

The: components. sorbed by the particles ofv porous contact material. may be recovered by sol.-' ventextraction or, if. it is not. desired to utilize this sorbed component, removal. by burning; may be. used. The; sorbent. particles. employed are re.- generated by this solvent extraction or burning" and may be. re-used a large number of times: before; requiring replacement with. fresh sorbent. Ther sollvent employed for. extracting. the sorbed: components may be; the: same. or a different one: from: that initially used in fillingthe. pores of the sorbent with vapor- If desired, morev than. one solventcan be employed. for the extraction operation, each. solvent. selectively extracting Variousotith'e' sorbed components.

The separation process described. herein: may r be carried out either in batch operation or as a. continuous process by adding. a suitable quantity of theabove: described sorbent particles: to. the material being treated or'percolating the mixture tosbeseparated through a bedof porous sorbent, the pores of which are substantially'filled with a. gaseous material soluble in the sorbed: component of. the mixture undergoing treatment.

The following detailed examples will: serve to illustrate the process of this invention without limiting. the same:

Example 1 irlg absorbed benzene.

8? givem aboye was about). seconds: The spheroidal-z particlesof gel were conducted out of. therbottonr; of. the column; into: a. stream oi: water and, .on re;- moval. from. the: water; base-exchanged with an aqueous. solution of? aluminium sulfate. and. waterwlasl'red. 'The: globules were; then slowly and; ior-mly dried in superheated steam .at about; 3002" F: until shrinkagewas substantially complete and the drying was: continued at a gradually increasing temperature upztos about 1050" which temperature was maintained for 0.5 hour. The; sili ca a'lumina gel resulting retained'its spheroidal. shape during the washing: and drying operations and had a final particle sizev of. about 4-20 mesh...

. The. bulk density of particles: so obtained" wasbetween: about 0.4 and 111 grams per cubic centimeter and the average pore diameter was. be-- tween about 20' and about 125 Angstrom units;

A quantity of the'above prepared gel particles was soaked in benzene until all-the airhad been: displaced from the gel pores. The excess benzene was then decanted oft and the gel particles weresubjected to a vacuum of lessthan 1 millimeter of mercury for 30 minut'esto vaporize the remain-- Whilethe gel particles werestill under vacuum, an equalweight of min-- eral' oil was added thereto. The vacuurn'was then broken and the absorption process proceededat atmospheric pressure. The oil employed had a Saybolt Universal viscosity of 108.1 seconds at 210 R, a color (Lovibond) of 155, and was refined by solvent-treating a Mid-Continent residue. Contactbetween said oil andthe gel particles'was'maintained for6 hours. at 75 F. The oil'i not taken up by the particles. was filtered off" (unabsorbed oil). The oil adhering to the outer surface waswashed off with a solvent and recovered" (wash). The oil absorbed in the gel pores was extracted with a solvent mixture ofequal' volumes of' benzene and methyl-ethyl ketone, and. recovered.

The above procedure was repeated for purposesv of comparison, using. gel particles in which. the air had not. been. displaced. with. benzene. vapor..

The following properties. were observed in the absorbed oil resulting from each operation;

T'able III."

Yield of Ab- Viscosity of Color of Ab- Mate'rial in Gel Pores sorbed'Oil' Absorbed Oil sorbed Oil Before Contacting (percent (S. U. V. at (Loviboud Wt.) 210 F.)

Benzenevapor 27.6 77.4 141 Air l2. 9' 71. 2' I7 The above results clearly in'dicatethat the rate of absorption of the gel particles has been more than doubled without the selectivity of the operation being'appreciably affected when air normally present in the gel pores was displaced by benzene vapor.

While the process of the present invention is not to" be limited by any theory, it would appear that the ability of benzene vapor and like materials to condense and dissolve in the oil being absorbed considerably increases the rate of absorption since the resistance to absorption offered by a non-condensable, slightly soluble gas such as airis' thereby eliminated.

A series of experiments carried out in a manner similar to that described above in Example 1" further showed that; the nature of the material" present in the gel pores has considerable" effect on the rate and selectivity of the operation. The results of these experiments are tabulated below:

10 pore size distribution of pores, and particle size are of fundamental importance to the selective Table IV Contacting Conditions Yields (Per Cent Wt.) S. U. V. 210 F., Seconds Material in Gel Pores Example B Absorb efore Contacting ent/Oil Time, Temp, Absorbed Unabsorbed Absorbed Unabsorbed Ratio Hrs. O on Wash on Charge Oil Wash Oil (by Wt.)

Cold Benzol Vapor 1 6 75 27. 6 13. 7 56. 4 108.1 77. 4 125.5 128. 6 Air 1 6 75 12. 9 28. 7 57. 6 108. 1 71. 2 112v 4 116. 7 Hot Benzol Vapor 1 6 75 26. 9 20.1 52. 8 108. 1 74. 7 128. 6 1268 Cold Naphtha Vapor.. 1 6 75 28. 4 13. 6 57. 1 108v 1 67. 5 130. 8 131. 2 Hot Naphtha Vapor.. 1 6 75 16. 9 28. 4 53. 6 108.1 67. 9 105. 113. 7 Vacuum (0.1 mm. Hg). 1 6 75 12. 4 27. 4 58.0 108.1 67. 8 111. 9 120. 6 Air 1 20 150 38. 6 17. 6 41.0 108.1 81. 4 144. 139.0 Carbon Dioxide. 1 150 40. 4 20. 1 38. 5 108.1 79. 2 133.0 137. 7 Nitrogen 1 20 150 39. 2 18. 8 39. 5 108.1 78. 2 145. 9 145v 3 M. E. K. (Liquid) 1 20 150 18.6 19. 7 61.0 108.1 95.1 111.8 109.6 Benzol (Liquid) 1 20 150 26. 3 8.8 63.0 108.1 103. 7 119. 5 111.1

Viscosity Index Color (Lovlbond, 34 Cell) Estimated Example Mategzgrg ggllgfigiglgefore Absorbed Un bso bed Ab bed U bsorbed i i a r sor na 0 r0 ss Charge Oil Wash on Charge Oi] Wash on Cold Bcnzol Vapor 103 105 102 104 155 14 250 250 Good.

Air 103 109 102 102 155 17 225 200 Do.

Hot Benzol Vapor.. 103 106 102 103 155 15 325 300 Do.

Cold Naphtha Vapor. 103 109 102 103 155 6 300 300 Do.

. Hot Naphtha Vapor. 103 109 105 103 155 7 250 200 Do. Vacuum (0.1 mm. Hg). 103 110 104 102 155 9 200 200 D0. Air 103 103 101 103 155 60 250 245 D0. Carbon Dioxide... 103 105 103 103 155 72 250 248 Do. Nitrogen 103 104 102 102 155 65 275 250 Do.

E. K. (Liquid)--. 103 98 104 104 155 165 160 150 Slight. Benzol (Liqui 103 96 104 105 155 190 209 190 None From the above table, it will be evident that the presence in the gel pores of gaseous materials which have the ability to dissolve in the sorbed component of the oil appreciably increase the rate of sorption. The present invention accordingly contemplates the use in a selective sorption medium of the type described of any gaseous material soluble in the sorbed component. Representative of the gaseous materials which may suitably be employed for displacing air from the pores of the contact material when mineral oil fractions are treated include solvent vapors such as those of benzene, naphtha, toluene, xylene, acetone, methyl-ethyl ketone, and other materials which dissolve in the sorbed oily component. The normally gaseous hydrocarbons, such as methane, ethane, and mixtures thereof, may also be used as a displacing gaseous material when mineral oil fractions are treated in accordance with the procedure of this invention. However, preferably, the aforementioned solvent vapors will be employed and particular preference is accorded those vapors which dissolve in the sorbed component at an appreciable rate, since the rate of sorption is thereby increased. Displacement of the air contained in the pores with a non-condensable gas, on the other hand, such as carbon dioxide or nitrogen, had no significant effect on either the rate or selectivity or the sorption process. Evacuating the gel sorbent particles before addition of the oil did not appear to have any significant effect on the operation. Saturation of the gel particles with liquids such as benzene, or methyl-ethyl ketone, on the other hand, greatly reduced the amount of oil that could be sorbed and almost completely destroyed the selectivity of the sorption process.

It is to be understood that in addition to the nature of the material present in the pores of the particle-form sorbent medium employed, the

sorption process under the particular condition of time and temperature of contact employed. Porous contact materials having a structure corresponding to that of an inorganic oxide gel having a substantially uniform porosity of low macropore volume with an average pore diameter not exceeding about 125 Angstrom units function as excellent sorbents in the present process. It should be noted that clay and various pelleted or extruded, synthetic siliceous composites, such as those employed in the cracking of petroleum hydrocarbons, are not effective sorbents for use in the present selective separation process. These materials contain, in addition to the small pores present in the gel structure, relatively large voids having pore diameters of 100010,000 Angstrom units and larger, which render the material ineffective for use as a sorbent in the present invention.

This application is a continuation-in-part of co-pending application Serial Number 709,788; filed November 14, 1946, now abandoned.

I claim:

1. A process for separating a liquid mixture of hydrocarbons having components of differing molecular volume, which comprises contacting said mixture with a porous particle-form sorbent material in which the pores are mostly micropores and the volume of pores having radii greater than about Angstrom units is less than about 30 per cent of the total porevolume, the air normally contained in the pores of said sorbent material being at least partially re-v placed by a gaseous material which is appree ciably soluble in the lower molecular volume components of said mixture, chemically inert under the conditions of contact and present in such proportion as to effect a noticeable increase in the rate of sorption as compared with a sorbent material having its pores wholly occupied by air,

:11 controlling the contact time, the temperature, and t e relative amounts of mixtureand sorbent to effect sorption of the lower molecular volume. components into the pores of said sorbent, while leaving substantially unsorbed the larger molecular volume components, thereby efiectin-g a-separation of the mixture 'into two fractions.

2. A process of separating a liquid mixture of hydrocarbons having components of difieringi molecular volume, which comprises sorbing the lower molecular volume components -of said mixture into the pores of a substantially micro- Jp'orous particle-form sorbent contact material, the particles of which are :greater than about'60 mesh size and in which less than 30 per cent of the total pore volume is occupied by pores having radii greater than about 100'Angstrom units,

the air normally contained in the pores of said sorbent material being at least partially replaced by a gaseous material which is appreciably-"sol 'ofthepo'r'es areirii'cropores and the volume of ,pores :having rad i-i greater than about 100 Angstrom units-is -less than-aboutBOper cent of the total ,pore volume and in which the particles are greater'than about-30 mesh size, the ainnormally contained-in ;-the pores 'of saidcontact material being at least partially :replaced prior to said contacting with a gaseous material which is appreciably. soluble 1 in the -lower amolecular volume components of said mixture, chemically-inert uhder the conditions of contactand present in jSilzi h proportion as toffect a noticeableincrease in"th'e rate of sorption as compared with a contact material having itspores wholly occupied by air, =whereby "sorption of the lower molecular volume-components 'ofsaid mixture into the p'ores of said "contact material takes lace, while the higher molecular volume components :of said mixture remain substantially unsorbed, thereby effecting a separation 'of "the mixture into two fractions. 7

A. "A process for separating a liquid mixture of hydrocarbons having*compoirentsof'diifering molecular volume, which "comprises contacting said mixture with uniform, substantially microporous, siliceous gel particle-shaving aparticle "size not le's's'than about 6'0 mesh and-in whichthe volume of pores having radii greater "than about 100 Angstrom "unit's is 'l'eSs "than about 30 percent of thetotaipore volume, the air normally contained in {the p'o'res of said gel particles being at least p'artially'replaced prior to "said contacting with ert under the conditions of contact and present a gaseous material which is'appre'ciably'soluble in V tnefiower molecular volume "components of "said mixture,"ichemically i'nertundertheconditions of Contact andpres'ent insuch proportion asto eflect a noticeable increase 'inthe 'ra'te ofsorption as compared with "gel particles the pores of which are "wholly occupied "by air,'whereby sorption of thellower molecular volume components of said mixture "takes .place, 'wliile the higher molecular 12 volume :components of said-mixture remain substantially unsorbed, therebyreffecting 'a separation of the mixture into two fractions.

5. A process for treating a liquid mixture of hydrocarbons-having components of difiZer-ing molecular volume by selective sorption of the lower molecular volume, 'less viscous components from the higher molecular volume, more viscous-components, which comprises contacting said mixture with uniform, substantially microporous inorganic :oxide gel particles having a particle size not less than about 60 mesh anda'total .pore volume made up mostly of micropores, there being less than about 30 per cent of pores having radii greater than about IOO'Angstrom units, the air normally contained in the pores of said .gel particles being at least partially replaced prior to said contacting with a gaseous material which is appreciably soluble in the lower molecular volume cemponents of=saidmixture cheniically inin such proportion as to effect a noticeable increase in the rate idf 'sorption 'as compared with =g'e1 particles :the 'pores of which are wholly occupied by air, whereby the low viscosity, low molecular volume components -of said mixture "are #sorbed into the pores of said gel particles, while the high viscosity, highm'o'lecular weight com- "ponents remain unsorbed, thereafter separating the original mixture and 'the other a greater visicosity than :the original mixture.

I 6. A process for treating a :liquid mixture of hydrocarbons having componentsof difiering-molecular volume by selective sorption of the .lower molecular volume, :less'viscous components from 'the higher molecular violu me more viscous components, which *comprises contacting said 'mixture with uniform, substantially microporous, siliceous gel :particles' having a particle size not less than-about 30mesh and a total pore volume made up mostly of -micropores, ::there :being less than about 30 {per cent of pores having radii greater than (about Angstrom units, the air normally contained in-the pores of said ;gel1 partioles being at least partially :replacedipriorto said contacting with a gaseous materialwhichis appreciably soluble in :the lower molecular volume components of said mixture, chemically inert under IhG-COhdliiiOIlSiOf contact :and present :in suchc proportion as torefiecta noticeable increase in the rataof-sorption as compared :withigelypan ticles the pores of which are wholly occupied by air, whereby thelow viscosit-y,1llow.inolecularvolume comp'onentsof said mixtureare sorbed into the. pores=of saidgel ,particles,:while the high viscosity, high molecular volume components :re-- main unsorbed, thereafter :separating: said t'gel particles from said unsorbedcomponents and-iremoving the sorbed I components from the pores'rof said 1gel particles to efiect a separation of the components of said mixture :into two fractions, one having a lower sviscosity than the original mixture and theother :agreater viscosity'thanithe original :mixture. 7

7. A:-processf0rtreating=a mineral oil-fraction, which comprises contacting said oil 'with [a mat-- ticle-form contact material [of substantial ,;.particle size as distinguished I from :powderedicontact material, said contact material bein of a porous structure, wherein iless than 30 :per ..cent of the total pore volume is occupied by pores of greater than about 100 Angstrom units radius, the air normally contained in the pores of said contact material being at least partially replaced prior to said contacting with a gaseous material which is appreciably soluble in the lower molecular volume components of said oil, chemically inert under the conditions of contact, and present in such proportion as to effect a noticeable increase in the rate of sorption as compared with a contact material having its pores wholly occupied by air, controlling the contact time, the temperature, and the relative amounts of oil and contact material to effect sorption of the lower molecular volume components of said oil into the pores of said contact material, while leaving unsorbed the larger molecular volume components, thereby effecting a separation of the oil into two fractions, one fraction comprisin tthe lower molecular volume components and having a viscosity substantially less than that of the original oil and the other fraction comprising the larger molecular volume components and having a viscosity substantially greater than that of the original oil.

8. A process for treating a mineral oil fraction, which comprises contacting said oil with a porous inorganic oxide gel contact material consisting of particles having an average diameter greater than about 0.022 inch and having less than 30 per cent of its pore volume taken up by pores of radii greater than about 100 Angstrom units, the remaining pore volume being taken up by smaller pores, the air normally contained in the pores of said contact material being at least partially replaced prior to said contacting with a gaseous material which is appreciably soluble in the lower molecular volume components of said oil, chemically inert under the conditions of contact, and present in such proportion as to effect a noticeable increase in the rate of sorption as compared with a contact material having its pores wholly occupied by air, controlling the contact time, the temperature and the relative amounts of oil and contact material to effect sorption of the lower molecular volume components of said oil into the pores of said contact material, while leaving unsorbed the larger molecular volume components, thereby effecting a separation of the oil into two fractions, one fraction comprising the lower molecular volume components and having a viscosity substantially less than that of the original oil and the other fraction comprising the larger molecular volume components and having a viscosity substantially greater than that of the original oil.

9. A process for separating a mineral oil fraction into components of differing molecular volume by selective sorption of the low viscosity, light-colored components from the higher viscosity, dark-colored components, comprising contacting said oil with uniform, substantially microporous inorganic oxide gel particles having less than about 30 per cent of their pore volume taken up by pores of radii greater than about 100 Angstrom units, the remaining pore volume being taken up by smaller pores and having a particle size not less than about 30 mesh, the air normally contained in the pores of said gel particles being at least partially replaced prior to said contacting with a vapor which is appreciably soluble in the low viscosity, light-colored components of said oil, chemically inert under the conditions of contact and present in such proportion as to effect a noticeable increase in the rate of sorption as compared with gel particles the pores of which are wholly occuped by air, whereby sorption of the low viscosity, light-colored components of said oil into the pores of said particles takes place, while the high viscosity, dark-colored components remain unsorbed, thereafter separating said gel particles from said unsorbed components and removing the sorbed components from pores of said particles to effect a separation of said oil in two fractions, one having a lower viscosity and a lighter color than the original oil and the other having a greater viscosity and a darker color than the original oil.

10. A process for separating a mineral oil fraction into components of differing molecular volume by selective sorption of the low viscosity, light-colored components from the higher viscosity, dark-colored components, comprising contacting said oil with. uniform, substantially microporous siliceous gel particles having less than about 30 per cent of their pore volume taken up by pores of a radii greater than about Angstrom units, the remaining pore volume being taken up by smaller pores and having a particle size not less than about 60 mesh, the air normally contained in the pores of said gel particles being at least partially replaced prior to said contacting with a vapor which is appreciably soluble in the low viscosity, light-colored components of said oil, chemically inert under the conditions of contact and present in such proportion as to effect a noticeable increase in the rate of sorption as compared With gel particles the pores of which are Wholly occupied by air, whereby sorption of the low viscosity, light-colored components of said oil into the pores of said particles takes place, while the high viscosity, dark-colored components remain unsorbed, thereafter separating said gel particles from said unsorbed components and removing the sorbed components from the pores of said particles to effect a separation of the oil into two fractions, one having a lower viscosity and a lighter color than the original oil and the other a greater viscosity and a darker color than the original oil.

11. A process for treating a petroleum lubricating oil fraction, which comprises contacting said fraction with a porous particle-form sorbent material in which the pores are mostly micropores and the volume of pores having radii greater than about 100 Angstrom units is less than about 30 per cent of the total pore volume, the air normally contained in the pores of said sorbent material being at least partially replaced prior to said contacting with a gaseous material which is appreciably soluble in the low viscosity components of said oil, chemically inert under the conditions of contact and present in such proportion as to effect a noticeable increase in the rate of sorption as compared with a sorbent material having its pores wholly occupied by air, controlling the contact time, the temperature, and the relative amounts of oil and sorbent to effect sorption of the low viscosity, light-colored components of said oil into the pores of said sorbent, while the high viscosity, dark-colored components of said oil remain unsorbed, thereby effecting a separation of the components of said oil into two fractions, one having a lower viscosity and a lighter color than the original oil and the other a greater viscosity and a darker color than the original oil.

12. A process for separating a petroleum lubricating oil fraction by selective sorption of the low viscosity, light-colored components from the higher viscosity, dark-colored components, comprising contacting said oil with uniform, substantially microporous inorganic oxide gel particleshaving iless thaniabout' 30 'per cent of their ,pore volume taken 'aup by pores having radii greater "than about .;100 ,Angstrom units, the remaining "pore :volume being "taken up by smaller pores and :having :a :particle size not less than .abou'tfiO mesh, thezaira-normallyicontained in the :poresof :saidgel particles being at'least partially replaced prior zto;said -:contacting with .a' vapor which is appreciably solublein the low viscosity, flight-coloredcomponents :of said oil, chemically inert under the conditions of contact and-present in such proportion .as 130 effect a noticeable increase in-the rate :ofsorption ascompared with .geLparticles the poresiof which are wholly occupied lay-air, whereby sorptionofithe low viscosity, light-colored components .of said oil into the pores :of said s-gel particles takes place, while the :high viscosity, dark-colored components remain unsorbed, thereafter separating saidgel particles from said unsorbed componentsand removing the sorbed components :from the pores .of said gel particlesto effect aseparation of the components of said oilinto two fractions,;one'having a lower viscosityand .a lighter color than the original oil andthe other'a 'greaterxviscosity and adarker color than the .original oil.

:13. A process forseparatinga petroleum lubricating oil fractionby selective sorption of the low viscosity, flight-colored components from the higher viscosity, dark-colored components, comprising contacting said oil with uniform, substantially microporous---inorganic oxide-gel particles having a particle size not less than-about 30 mesh and in which most of the pores are micropores, "the volume of pores having radii greater thaneabout 100 Angstrom unitsbeing less than about 30 per cent of the total pore-volume, the air normally contained in the pores of said gel particles being at least partially replaced prior to said contacting with a vapor which-is appreciablysoluble in the low viscosity, light-colored components of said'oil, chemically inert under the conditions of contact and present in "such proportion as to effect a noticeable increase in the rate of sorption as compared with gel particles the pores of whichare wholly occupied'by air, whereby sorption of the low viscosity, lightcolored components of said oil into the pores of saidgelparticles ta'kes'place, while the high viscosity, dark-colored components remain unsorbed, thereafter separating said gel particles from said unsorbed components, washing said particles with a suitable oil solvent to remove oil'aa'dhering (t0 Tithe :surface @thereof, rsolventextracting the-sorbed components from the pores :of said gel particles, and recovering said sorbed :low viscosity, light-colored components from the higher viscosity, .darkecolored components, mom- =prising contacting said oil with uniform, :substantially microporous siliceous gel particles in which the .percentageof pore volume dUBtOiEDOYES having radii greaterthan about 1.00 Angstrom units is less than about 30, said particles having a size not less than-abouti30 mesh.an'dthe-.-air

normally contained in the pores of said gelxpariticles being at'least :partially replaced prior to said contacting with a vapor whichis appreciably soluble in the low viscosity, light-colored components of said oh, chemically inert under :the conditions of contact and present in such .proportio'n-asto effect anoticeable increase infthe rate of -sorption as compared with gel particles the poresof which are wholly occupied byair, whereby the low viscosity, light-colored components of said oil are sorbed into the pores of said gel particles, while the high viscosity, darkcolored components remain unsorbed, thereafter separating said gel particles from said unsorbed components, washing said particles to remove oil adhering to the surface thereof with a suitable oil solvent, solvent-extracting the sorbed components from the pores of said gel particles, and recovering saidsorbed components fromthe resulting extract to yield a fraction having a lower viscosity and a lighter color than the original oil.

DONALD A. HERMANSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,665,264 Holmes Apr. 10, 1928 2,331,353 Stoeweneret al, 'Oct. 12, 1943 2,337,944 'Stoewener et al Dec. 28, 1943 2 ,384,311 Kearby Sept. 4,1945 2,384,946 Marisic Sept. 18, 1945 2,398,101 Lipkin Apr. 9, 1946 2,441,572 ,Hirschler et a1 May 18, 1948 

